#VU91680 Use of uninitialized resource in Linux kernel - CVE-2021-47136

Vulnerability identifier: #VU91680

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-47136

CWE-ID: CWE-908

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to use of uninitialized resource within the tcf_classify_ingress() function in net/sched/cls_api.c, within the mlx5e_tc_update_skb() function in drivers/net/ethernet/mellanox/mlx5/core/en_tc.c, within the mlx5e_rep_tc_update_skb() function in drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

---

External links
https://git.kernel.org/stable/c/ac493452e937b8939eaf2d24cac51a4804b6c20e
https://git.kernel.org/stable/c/86ab133b695ed7ba1f8786b12f4ca43137ad8c18
https://git.kernel.org/stable/c/9453d45ecb6c2199d72e73c993e9d98677a2801b

---

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.